The lift cylinders on my D4/D4D do not move together; the right lifts the blade 4+ inches before the left moves and it lowers it 4+ inches before the left moves. Once the blade has reached maybe a foot off the ground the blade levels but on the way down it lists to one side until it hits the ground. Both cylinders and all their various pivots are freshly replaced/rebuilt. "67 model 78A7177 serial number.
Hang the blade over the ege of something so you can work it full stroke to bleed the air out.
I had wondered about trapped air after having a hard time getting the pump to pull fluid out of the tank initially so had full cycled the cylinders by using them to raise the front of the machine. The hydraulic fluid showed a good bit of aeriation after that. Now that the machine has set a couple days for the air to escape I will try your suggestion, once again, thanks!!